KR930006213B1 - Cerment alloy containing nitrogen - Google Patents

Abstract

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Description

[Name of invention]

Nitrogen Cermet Alloys

[Brief Description of Drawings]

1 shows the structure of a typical twist drill.

FIG. 2 is a distribution diagram of the particle size of the hard dispersed phase showing the distribution of the particle size of the hard dispersed phase of the cermet. FIG.

Preferred form for carrying out the invention.

Detailed description of the invention

[Technical Field]

The present invention relates to a high-quality nitrogen-containing cermet alloy excellent in wear resistance and toughness and resistant to high-speed cutting, and a drill made of the cermet alloy.

[Background]

The drill is a cutting tool used for drilling, such as steel, the structure of the twist drill is shown in FIG. 1 as an example. Twist drills generally have pickled portions (1) provided for punching, and shank portions (2) which serve to discharge the cutting material and attach it to chuck portions of cutting machines such as balls and the like, without being very involved in cutting operations. Doing.

In use, the drilled and shank sections are used under different load conditions. Therefore, the toughness required for each part of the drill is different. For example, wear resistance, welding resistance, and the like are required at the cutting edge of the cutout portion, and toughness for preserving strength as a tool is required at the shank portion. In addition, the cutting edges at the center portion and the outer circumferential portion of the cutout portion are significantly different, so the required properties are different. In order to meet such complicated requirements, various things have been developed as a material of a drill conventionally.

Conventionally, typical drill materials are high speed steel and cemented carbide. High speed steel is rich in toughness but low in wear resistance and unsuitable for high speed cutting. Carbide alloys, on the other hand, have excellent wear resistance and precision characteristics, but are brittle and, for example, used in machine tools with low rigidity.

As such improvements, a structure in which hard TiN is coated on a cut portion of high-speed steel, or a cut portion is attached to a cemented carbide is considered. However, coating the pickled portion has the drawback that at the time of regrinding the drill, at least the coating layer of the previous drawing side is removed, and thus the placenta of the coating effect is lost. In addition, the structure of attaching the cemented carbide to the pickled portion has a drawback that does not apply to hard erase and deep hole processing since the adhesive itself is inherently poor in thermal and mechanical strength.

In recent years, in order to improve wear resistance and toughness, a structure in which cemented carbides (P30 and D30) of different materials are attached (Japanese Utility Model Publication No. 58-143115) or metallurgically integrally bonded together (Japanese Utility Model Publication No. 62-46489), and the center of the drill and the outer periphery of the required characteristics of the difference between the center of the cemented carbide and the material of the outer periphery of the two-layer structure (Japanese Patent Publication) Japanese Patent Application Laid-Open No. 62-218010) or a method of forming the double structure by injection molding (Japanese Patent Laid-Open No. 63-38501, 38502) and the like have been proposed. Moreover, in order to improve the welding resistance of a drill, the structure which comprised the drill material by the cermet (Japanese Patent Laid-Open No. 62-292307), etc. are mentioned. In these conventional examples, the cemented carbide was made into coarse grains or a high bonding phase for the purpose of improving the toughness of the shank portion of the drill. However, this may in turn lower the strength of the material or lower the elastic strain, This can cause damage during drilling, due to movement or unstable rotation of the machine.

As described above, improvements from individual viewpoints have been made to the complicated demands of the drill. However, none of these conventional structures completely satisfies all the characteristics requirements of the drill.

[Initiation of invention]

It is an object of the present invention to provide a nitrogen-containing cermet alloy which exhibits particularly excellent wear resistance and toughness.

Another object of the present invention is to provide a cermet drill composed of a cermet having excellent abrasion resistance and welding resistance at the cut portion of the drill and having sufficient characteristics in the shank portion.

It is still another object of the present invention to provide a sintered hard alloy drill made of a WC cemented carbide having excellent wear resistance and weld resistance in the cutout portion of the drill and the shank portion having the necessary properties.

The present inventors intended to improve the wear resistance and weldability, among other properties required for the drill. The inventors thought that it was necessary to use a nitrogen-containing cermet as a main component of titanium (Ti) in order to improve wear resistance and welding resistance. From there, experiments were carried out with various components of the cermet as a factor and a lot of valid knowledge was obtained. The present invention has been made based on this knowledge.

In the first aspect, the drill has the following characteristics.

(1) The hard dispersed phase of the cermet has a mixed structure of finely dispersed fine particles having a particle diameter of 0.2 to 1.6 µm and a hard phase of rough particles of 1 to 3 µm. The volume mixing ratio of the particulate hard phase to the hard phase of the coarse particles is 0.3 to 3.0. In this range, the generation and propagation of cracks due to the thermal shock received by the cutting edge of the drill at the time of use can be effectively suppressed. Preferably, the particle diameter of the particulate hard phase is 0.3 to 0.5 mu m, and the particle diameter of the hard phase of the coarse particles is 1.5 to 2.2 mu m.

(2) The hard disperse phase of the cermet is formed from one of the metals of Groups IVa, Va, and VIa of the periodic table, excluding titanium and titanium, or any of carbides, nitrides, and complex carbonitrides with two or more metals; The amount of titanium in the metal atom is 0.5 to 0.95 in atomic ratio. If the amount of titanium is less than 0.5, the abrasion resistance and the welding resistance of the cermet are insufficient. If the content exceeds 0.95, the sinterability of the cermet deteriorates.

(3) The ratio of nitrogen in the nonmetallic atoms included in the hard dispersed phase is 0.1 to 0.7 in atomic ratio. In other words, when the ratio of nitrogen is less than 0.1 in the atomic ratio, the effect of suppressing the growth of particles in the hard dispersed phase during nitrogen sintering is not produced. If the content exceeds 0.7, the sinterability of the cermet is deteriorated.

(4) The amount of the binding metal phase contained in the cermet is 5% by weight to 30% by weight. If less than 5% by weight, the toughness of the cermet is insufficient to cause chipping in the use of the drill. Moreover, when it exceeds 30 weight%, abrasion resistance is lacking and big abrasion occurs in the drawing of a drill edge or a margin part.

In a second aspect, the drill has the following features.

(1) In order to suppress the occurrence and development of cracks due to thermal shock in the cutting edge of the drill, the volume mixing ratio between the fine grain having a particle diameter of 0.2 to 0.6 µm and the hard phase of the coarse grain having a grain diameter of 1 to 3 µm. Needs to be in the range of 0.3 to 3.0. More preferably, the particle diameter of the particulate hard phase is 0.3 to 0.5 µm, and the particle diameter of the hard phase of the coarse particles is 1.5 to 2.2 µm.

(2) In order to increase the toughness required for the shank portion, the hard dispersed phase of the cermet needs to have a particulate structure having a particle diameter of 0.2 to 0.6 mu m. The two cermets are similar in composition even if their characteristics are different from each other. Therefore, it is possible to form the joints continuously without using a discontinuous low strength bonding method such as adhesion or the like. Examples of the bonding method include bonding at the time of press (dryback) and bonding at the time of HIP.

Based on the above knowledge, in the second aspect, the cutout portion and the shank portion of the drill formed by the cermets having different compositions are joined together. The composition of each part of this drill and its characteristic are demonstrated next.

[I. Pickles]

A. Components of Hard Dispersed Phase

a. The hard dispersed phase is any one of carbides, nitrides, and complex carbonitrides of titanium and one or more metals of Group IVa, Va, and VIa metals of the periodic table excluding titanium, and titanium in the metal atoms included in the hard dispersed phase. The amount of is in the range of 0.5 to 0.95 in atomic ratio. Less than 0.5 lacks the wear resistance and weldability of the cermet. If the content exceeds 0.95, the sinterability of the cermet deteriorates.

b. The proportion of nitrogen in the nonmetallic atoms included in the hard dispersed phase is in the range of 0.1 to 0.7 in atomic ratio. If it is less than 0.1, the effect that the nitrogen atom suppresses grain growth of the hard dispersed phase during sintering will not occur. Also. If it exceeds 0.7, the sinterability of the cermet deteriorates.

c. The hard dispersed phase is a mixture of fine particles having a particle diameter of 0.2 to 0.6 mu m and a hard phase of coarse particles having a particle diameter of 1 to 3 mu m, and the volume ratio of the fine particles to the hard phase of the coarse particles is in the range of 0.3 to 3.0. Below 0.3, the toughness drops and chipping occurs at the edge of the drill. In addition, if it exceeds 3.0, thermal shock resistance deteriorates and thermal cracking occurs.

B. Amount of bound metal phase in cermet

a. The amount of binding metal phase contained in the cermet is in the range of 5% to 30% by weight. If it is less than 5% by weight, the toughness is insufficient and chipping occurs in the edge. Moreover, when it exceeds 30 weight%, abrasion resistance is lacking, and the drawing of a cutting edge and abrasion of a margin part become large.

[II. Shank part]

Because the shank requires high toughness, the difference in thermal expansion coefficient between the edge and the edge must be 1.0 × 10 ^-6 / ° C or less in order to realize a low Young's modulus that conforms to the bending load and good bondability with the edge. Do.

A. Components of Hard Dispersed Phase

a. The hard dispersed phase is formed of any one of carbides, nitrides, and complex carbonitrides of one or two or more of the metals of Groups IVa, Va, and VIa of the periodic table excluding titanium and titanium, and of the metal atoms included in the hard dispersed phase. The amount of titanium is in the range of 0.5 to 0.95 in atomic ratio. If it is less than 0.5, the adhesiveness with the edge part will deteriorate. If the content exceeds 0.95, the sinterability of the cermet deteriorates.

b. The proportion of nitrogen in the nonmetallic atoms included in the hard dispersed phase is in the range of 0.1 to 0.7 in atomic ratio. If it is less than 0.1, the hard-dispersed phase grows during sintering of the cermet, and a predetermined particle diameter cannot be obtained. If it exceeds 0.7, the sinterability of the cermet deteriorates.

c. The particle diameter of the hard dispersed phase has a fine particle structure of 0.2 to 0.6 mu m. If the particle diameter exceeds 0.6 mu m, the strength of the cermet deteriorates and sufficient toughness required for the shank portion cannot be maintained.

B. Amount of bound metal phase in cermet

The amount of binding metal phase contained in the cermet is in the range of 5% to 30% by weight. If it is less than 5% by weight, the strength is insufficient, and if it exceeds 30% by weight, the cermet causes plastic deformation. Moreover, if it is out of the said range, the difference of the thermal expansion coefficient with a edge part will become large and it is unpreferable.

Thus, in the second aspect, the cermet drill is formed by integrally joining the cut portions and the shank portions having compositions of different particle sizes.

The present inventors also obtained the knowledge that the use of a WC-based cemented carbide is desirable in order to satisfy the toughness and strength required for the shank portion of the drill. In the third aspect, a cermet having excellent wear resistance and weldability is used for the cut portion of the drill, and a WC cemented carbide having excellent toughness is used for the shank portion. The pickled portion and the shank portion are integrally joined. Next, the characteristic of this drill is demonstrated.

[I. Pickles]

A. Components of Hard Disperse Phase in Cermet

a. The hard dispersed phase is composed of titanium (Ti) and metal atoms contained in carbides, nitrides, and complex carbonitrides of one or two or more kinds of metals of Groups IVa, Va, and VIa of the periodic table excluding titanium, and are included in the hard dispersed phase. The amount of titanium in the range is 0.5 to 0.95 in atomic ratio. Less than 0.5 lacks the wear resistance and weldability of the cermet. If the content exceeds 0.95, the sinterability of the cermet deteriorates.

b. The proportion of nitrogen in the nonmetallic atoms included in the hard dispersed phase is in the range of 0.1 to 0.7 in atomic ratio. If it is less than 0.1, nitrogen does not produce the effect of suppressing grain growth of the hard dispersed phase upon sintering of the cermet. If the content exceeds 0.7, the sinterability of the cermet is deteriorated.

c. The hard dispersed phase is formed of a mixture of fine particles having a particle diameter of 0.2 to 0.6 μm and a hard phase of coarse particles having a particle size of 1 to 3 μm, and has a volume ratio of the fine particles to the hard phase of the coarse particles in a range of 0.3 to 3.0. Is in. In other words, less than 0.3, the toughness of the cermet deteriorates and chipping occurs in the drill edge portion. In addition, if it exceeds 3.0, thermal cracking occurs in the edge of the drill, which is a problem.

B. Amount of bound metal phase in the cermet

a. The amount of binding metal phase contained in the cermet is in the range of 5% to 30% by weight. If less than 5% by weight, the toughness of the cermet is insufficient and chipping occurs in the edge of the drill. In addition, when 30% by weight is added, the wear resistance is insufficient, which causes large wear on the drawing or the margin of the edge.

[II. Shank part]

A. WC cemented carbide is used for the shank portion of the drill. For example, when high-speed steel or the like is used, the coefficient of thermal expansion is large, so that cracks are likely to occur at the joint surface of the cutout due to the difference in thermal expansion with the cermet of the cutout. In addition, the Young's modulus of the high-speed steel is about one third of the WC-based alloy, and since the seismic resistance at the time of cutting is bad, the wear and defect of the cutout part are also promoted.

Example 1

Using a cermet alloy having various material compositions and particle size distributions, a drill having a diameter of 10 mm was fabricated from each single material and its processing performance was experimentally investigated. Table 1 shows the composition and the like of various alloys provided in the experiment. A to C denote the present invention, and D to H denote the comparative product used for comparison. In the comparative products, D and E are used to compare the ratio of nitrogen atoms in the nonmetallic atoms of the hard dispersed phase. In addition, the comparative product F is used as a comparative example of the ratio of the particle ratio of hard dispersion phase. In addition, the comparative products G and H are used for the comparative example of the quantitative ratio of a binding phase. Thus, comparative products D to H and A to C of the present invention were compared with each other.

TABLE 1

* 1 Abundance ratio A / B of the hard phase particle size is volume ratio (refer FIG. 2).

Next, the conditions of the drilling performance evaluation test of the drill are shown in the second table. The performance evaluation test was performed on two types of conditions.

Test 1 is a drill's wear resistance evaluation test. That is, it is a test which performs a continuous hole drilling process to the lifetime by a drill damage or abrasion, and evaluates the edge condition.

Test 2 is a heat crack crack evaluation test of the drill. That is, it is a test which divides into a workpiece several times, drills a deep hole in the same place, and evaluates the edge condition after completion | finish of a predetermined punching process.

TABLE 2

In this experiment, the same cutting test was performed with the coated high drill and the coated carbide drill currently used for reference.

Table 3 shows the results of the drill's performance evaluation test. From the test results shown in Table 3, the following facts were found.

a. As shown in the results of the abrasion resistance test 1 in the comparison between the present inventions A to C and the comparative products D and E, materials having a large number of coarse particles in the hardness of the hard dispersed phase have a low shank strength and poor toughness due to sudden breakage. It turned out.

b. In the comparison between the present inventions A to C and the comparative product F, the particle size of the hard dispersed phase was excellent in the shank strength only, but it was found to be significantly lower in the heat crack resistance (test 2).

c. In the comparison between the present inventions A to C and the comparative products G and H, a small amount of the bonding phase (comparative product G) is inferior in toughness (test 1), and a large amount of the bonding phase (comparative product H) is abrasion resistant. It turned out to be falling (test 1 and test 2).

In comparing these experimental results, it was found that the present inventions A to C have excellent characteristics in all aspects such as wear resistance, thermal crack resistance, and toughness of the shank. In addition, it was found in Table 3 to display the superior properties compared to the coating high or coated supercarrier. In addition, the present invention is characterized by displaying performance equivalent to that of a new product even when subjected to regrinding again.

TABLE 3

Example 2

Table 4 shows the composition and particle size distribution of the cermet alloy used in the experiment. These cermet alloys were used to fabricate a 10 mm diameter drill from each single material and to investigate its perforation performance. In the alloy group shown in Table 4, for example, the group of alloys AA to FF focuses on the distribution of particles in the hard dispersed phase. In addition, the group of alloys GG to II mainly focuses on the ratio of nitrogen in a nonmetal atom. In addition, the group of alloys JJ to MM mainly focuses on the amount of bonding phase.

TABLE 4

(* 1) Abundance ratio (volume ratio) of hard phase particle size, (refer to FIG. 2)

(* 2) The present invention: for shank

〃: For blade tip

The performance evaluation test was carried out under the conditions shown in Table 5. That is, the wear resistance evaluation test and the thermal crack resistance evaluation test. The results of each test are shown in Table 6.

TABLE 5

TABLE 6

In the results of the group of alloys AA to FF, excellent wear resistance was observed in the alloys AA to DD having a relatively fine particle size of the hard dispersed phase. Alloys EE and FF caused an unexpected breakdown. As for the thermal crack resistance, the finer alloys AA and BB of the particle size showed poor results. As for the shank strength, alloy AA was the most excellent and tended to deteriorate as the grain size of the hard dispersed phase became rough (the order of alloys CC to FF).

Therefore, in the group of alloys AA to FF, alloys CC and DD were found to be excellent in wear resistance and thermal crack resistance, and alloy AA was excellent in shank strength.

In the alloys GG to II, it was found that the life of the alloy GG was short and that the alloy II fell from the shank strength.

In the group of alloys JJ to MM, alloy KK showed excellent shank strength and alloy LL showed excellent cracking resistance. As a result, alloy KK has a property suitable for the shank portion, and alloy LL has a property suitable for the edge portion.

In the results shown in Table 6, first, alloys CC, DD, HH, and LL were selected as alloys having suitable properties for the cut portions of the drill, and alloys AA and KK were selected as alloys having properties suitable for the shank portion of the drill. Several kinds of drills in which these alloys were integrally molded and fabricated were fabricated and tested for their performance evaluation. Table 7 shows the combination of the alloys used in the edge and shank portions of the drill and the results of the evaluation tests. The performance evaluation test was conducted in accordance with the conditions shown in Table 5. As a method of forming a bond between the edge portion of the drill and the shank portion, a method of joining alloys by thermal diffusion to each other, or a method of joining and molding the powders at the time of powder compression molding, and then integrating them at the time of sintering. In addition, the test results of the coating high drill and the coating superimposed drill currently used are also shown in Table 7 in parallel.

TABLE 7

Comparing the results of the performance evaluation test shown in Table 7 with Table 6, it is evident that any composite alloy of NN to QQ has abrasion resistance and thermal crack resistance and toughness. In addition, in the performance evaluation test shown in Table 6, for example, breakages generated unexpectedly in alloys EE and FF did not occur at all in the composite alloys NN to QQ. In addition, it was evident that the composite alloy had high quality without any change in all its properties even after regrinding the cut portions.

Example 3

The sintered hard alloy drill was formed by joining and sintering a cermet alloy in a cut portion and using a WC cemented carbide portion in the shank portion during molding press of a powder. Table 8 shows the composition of the sintered hard alloy drill provided in the performance test and the distribution of particle size and the cermet alloy portion of the drill used for comparison. In Table 8, alloys DDD and EEE of the comparative product are mainly used in consideration of the ratio of nonmetallic atoms included in the hard dispersed phase. In addition, the alloy FFF of the comparative product is used paying attention to the distribution of the particle size of hard dispersion phase. In addition, comparative alloys GGG and HHH are used paying attention to the ratio of the binding metal phase contained in the cermet.

TABLE 8

(* 1) abundance ratio of hard phase particle size; (Volume ratio), (see Figure 2)

The performance evaluation test of the drill was carried out under the conditions shown in Table 9 by producing a drill having a diameter of 10 mm using the materials of alloys AAA to HHH shown in Table 8. This performance evaluation test mainly consists of two tests: abrasion resistance test and thermal crack resistance test.

TABLE 9

Table 10 shows the results of the drill performance evaluation test. Referring to Table 10, first, in the comparison of alloys AAA to CCC, alloys DDD and EEE, alloys DDD and EEE were particularly poor in toughness of the edge, and as a result, sudden breakage occurred during the test of test ①.

In comparison of alloys AAA to CCC and alloy FFF, it was found that alloy FFF lacked thermal crack resistance.

In comparison with alloys AAA to CCC, alloys GGG and HHH, alloy GGG was found to have poor thermal cracking resistance and a very short lifespan. It has also been found that the wear resistance is less in alloy HHH.

For comparison, this performance test was also performed in parallel with the coating highs or coated carbide drills currently in use. In the comparison between these drills and drills of alloys AAA to CCC, it is clear that the drill of the invention is excellent in any test.

Performance evaluation tests were also conducted on the drills formed of a single material of alloys AAA to CCC, for example, alloy AAA, and a drill formed of a single material of WC cemented carbide. As a result, in the comparison between the alloy AAA of the present invention and the alloy AAA of the single material, the alloy-AAA of the present invention exhibits a characteristic improvement in strength. In addition, in the comparison between the alloy AAA of the present invention and the WC cemented carbide, it is clear that the alloy AAA of the present invention is also excellent in wear resistance and strength.

TABLE 10

Industrial availability

As described above, the nitrogen-containing cermet alloy according to the present invention may be advantageously used for drills, end mills, milling cutters, and the like, which require excellent characteristics in wear resistance, toughness and high-speed cutting properties.

Claims (4)

A hard dispersion phase composed mainly of carbides and nitride complex carbonitrides with titanium and one or more metals of Groups IVa, Va, and IVa of the periodic table excluding titanium, and bonds containing nickel and cobalt as main components In the nitrogen-containing cermet alloy formed of a metal phase, the hard dispersed phase includes a metal atom group including titanium and a nonmetal atom group including nitrogen, and the amount of titanium in the metal atom group is 0.5 to 0.95 in an atomic ratio. The amount of nitrogen in the nonmetallic atom group is 0.1 or more and 0.7 or less by atomic ratio, and the hard dispersed phase has a mean particle size of 0.2 μm or more and 0.6 μm or less and a coarse particle diameter of 1 μm or more and 3 μm or less. And a particle group, wherein the particle group has a volume ratio of 0.3 to 3 to a coarse particle group, and the bonding metal phase has a ratio of 5 contained in the nitrogen-containing cermet alloy. Nitrogen-containing spent metteu alloy, characterized in that% by weight or less than 30% by weight. A hard dispersed phase composed mainly of carbides, nitrides, and complex carbonitrides with titanium and one or more metals of Groups IVa, Va, and IVa of the periodic table excluding titanium, and nickel and cobalt as main components In a cermet alloy composed of a nitrogen-containing cermet formed of a binding metal phase, the hard dispersed phase includes a metal atom group including titanium and a nonmetal atom group including nitrogen, and the amount of titanium in the metal atom group It is 0.5 or more and 0.95 or less by its own ratio, and the quantity of nitrogen in the said nonmetallic atom group is 0.1 or more and 0.7 or less by atomic ratio, The said hard-dispersed phase has a microparticle group with an average particle diameter of 0.2 micrometer or more and 0.6 micrometer or less and an average particle diameter of 1 micrometer or more. 3 micrometers or less coarse particle group, The said microparticle group has a volume ratio with respect to a coarse particle group of 0.3 or more and 3 or less, The said bonding metal phase is the ratio contained in a cermet. The cermet drill, characterized in that the ratio is 5% by weight or more and 30% by weight or less. Hard disperse phase composed mainly of carbides, nitrides and complex carbonitrides with titanium and one or more metals of Groups IVa, Va and IVa of the periodic table excluding titanium, and nickel and cobalt as main components In a cermet drill consisting of a cermet formed of a binding metal phase to be formed and a cutting portion for cutting the workpiece, and a portion of which is attached to a fixed attachment portion of the cutting machine, the hard dispersed phase comprises titanium Containing a non-metal atom group including a metal atom group and nitrogen, wherein the amount of titanium in the metal atom group is in an atomic ratio of 0.5 or more and 0.95 or less, and the amount of nitrogen in the non-metal atoms is in an atomic ratio of 0.1 or more and 0.7 or less, The binding metal phase has a proportion of 5 wt% or more and 30 wt% or less in the cermet, and the dispersing phase of the cermet forming the cutout is an average particle. A fine particle group having a diameter of 0.2 µm or more and 0.6 µm or less and a coarse particle group having an average particle diameter of 1 µm or more and 3 µm or less, wherein a volume ratio of the fine particle group to the rough grain group is 0.3 or more and 3 or less, and the shank portion The cermet drill of the cermet constituting the cermet, wherein most of the cermet is composed of a particle group having a particle diameter of 0.2 µm or more and 0.6 µm or less. A small crystalline alloy drill having a cutout for cutting a workpiece and a shank portion of which a part is attached to a fixed attachment position of a cutting machine, wherein the cutout includes the IVa, Va, and Va of the periodic table excluding titanium and titanium. Consists of a cermet formed of a bonding metal phase composed mainly of one or two or more kinds of carbides, nitrides, and complex carbonitrides of Group IVa metals, and the hard dispersed phase includes a metal atom group including titanium and nitrogen. Including a nonmetal atom, the amount of titanium in the said metal atom group is 0.5 or more and 0.95 or more by atomic ratio, The quantity of nitrogen in the said nonmetallic atom is 0.1 or more and 0.7 or less by atomic ratio, The said hard-dispersed phase has an average particle diameter of 0.2 micrometer or more A volume ratio of the fine particle group having a particle size of 0.6 μm or less and the coarse particle group having an average particle diameter of 1 μm or more and 3 μm or less, and the fine particle group to the coarse particle group 0.3 or more and 3 or less, and the bonding metal phase has a ratio of 5 wt% or more and 30 wt% or less in the cermet, and the shank portion is integrally bonded with the cut portion and is composed of WC cemented carbide containing cobalt. Sintered hard alloy drill.